U.S. patent number 7,572,742 [Application Number 10/592,503] was granted by the patent office on 2009-08-11 for equipment and method for processing semiconductor.
This patent grant is currently assigned to Tokyo Electron Limited. Invention is credited to Tsutomu Hiroki.
United States Patent |
7,572,742 |
Hiroki |
August 11, 2009 |
Equipment and method for processing semiconductor
Abstract
Semiconductor processing equipment includes a transfer chamber
(3) having a plurality of transfer ports (33) arranged at different
positions in a lateral direction. A process chamber (4A) for
performing a semiconductor process to a substrate (W) to be
processed is connected with the transfer chamber (3) through one of
the transfer ports. A transfer arm device (5) is arranged in the
transfer chamber (3) so as to transfer the substrate (W) through a
plurality of the transfer ports (33). A drive mechanism (55) is
arranged so as to extend and retract the transfer arm device (5)
and to turn it in a vertical axis direction. Inclination adjusting
mechanisms (6A-6C) are arranged so as to adjust the inclination of
the transfer arm device (5).
Inventors: |
Hiroki; Tsutomu (Nirasaki,
JP) |
Assignee: |
Tokyo Electron Limited (Tokyo,
JP)
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Family
ID: |
35125360 |
Appl.
No.: |
10/592,503 |
Filed: |
February 24, 2005 |
PCT
Filed: |
February 24, 2005 |
PCT No.: |
PCT/JP2005/003035 |
371(c)(1),(2),(4) Date: |
September 12, 2006 |
PCT
Pub. No.: |
WO2005/098934 |
PCT
Pub. Date: |
October 20, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070275486 A1 |
Nov 29, 2007 |
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Foreign Application Priority Data
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Mar 30, 2004 [JP] |
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2004-100270 |
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Current U.S.
Class: |
438/800;
414/744.5 |
Current CPC
Class: |
H01L
21/67167 (20130101); H01L 21/67742 (20130101); H01L
21/67748 (20130101); H01L 21/681 (20130101) |
Current International
Class: |
H01L
21/00 (20060101); B66C 23/00 (20060101) |
Field of
Search: |
;438/800 ;414/744.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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6 210066 |
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Aug 1994 |
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JP |
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10 233426 |
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Sep 1998 |
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JP |
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11 163083 |
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Jun 1999 |
|
JP |
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411163083 |
|
Jun 1999 |
|
JP |
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11 330204 |
|
Nov 1999 |
|
JP |
|
2001 15575 |
|
Jan 2001 |
|
JP |
|
2002 222844 |
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Aug 2002 |
|
JP |
|
Primary Examiner: Coleman; W. David
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt, P.C.
Claims
What is claimed is:
1. A semiconductor processing equipment comprising: a transfer
chamber having a plurality of transfer ports disposed at different
positions in a lateral direction; a process chamber connected to
the transfer chamber via one of the plurality transfer ports which
performs a semiconductor processing on a substrate to be processed;
a transfer arm device arranged in the transfer chamber which
transfers the substrate to be processed via the plurality of
transfer ports; a drive mechanism which extends and retracts the
transfer arm device and turns the transfer arm device around a
vertical axis direction; an inclination adjusting mechanism which
adjusts an inclination of the transfer arm device; and a rocking
table rockable with respect to the transfer chamber which supports
the transfer arm device, wherein the inclination adjusting
mechanism adjusts an inclination of the transfer arm device by
adjusting an inclination of the rocking table.
2. The equipment of claim 1, wherein the drive mechanism is
provided on the rocking table.
3. The equipment of claim 1, wherein the inclination adjusting
mechanism has a plurality of adjusters which separately raise and
lower at least three locations disposed along a circumference of
the rocking table.
4. The equipment of claim 1, wherein the transfer chamber is a
vacuum transfer chamber; the plurality of transfer ports are
connected with a plurality of vacuum process chambers via
respective gate valves; and the process chamber is one of the
plurality of vacuum process chambers.
5. The equipment of claim 1, further comprising a detector which
detects data on an inclination of the transfer arm device.
6. The equipment of claim 3, further comprising a control unit
which drives the adjusters based on data on the inclination of the
transfer arm device.
7. The equipment of claim 3, wherein the rocking table is supported
at a single location of the bottom portion by a universal
joint.
8. The equipment of claim 7, further comprising a pliable wall
formed between the rocking table and a wall of the transfer chamber
which separates a space where the plurality of adjusters and the
universal joint are arranged from an inner space of the transfer
chamber and also which allows an operation of the rocking
table.
9. The equipment of claim 5, further comprising a storage unit
which stores the data detected by the detector and a control unit
which controls the inclination adjusting mechanism based on the
data stored in the storage unit.
10. The equipment of claim 5, wherein the detector has a plurality
of optical sensors spaced from each other in a lateral direction,
each which measures a distance to a facing portion thereof.
11. The equipment of claim 10, wherein the transfer arm device has
a hand and the plurality of optical sensors is disposed on a bottom
surface of the transfer arm device hand.
12. The equipment of claim 10, wherein the plurality of optical
sensors is provided at the transfer ports connected to the process
chambers.
13. The equipment of claim 10, wherein the plurality of optical
sensors are arranged on a dummy substrate serving as a substitute
for the substrate to be processed.
14. The equipment of claim 10, wherein each of the plurality of
optical sensors has a light emitting unit which emits light to the
facing portion thereof and a light receiving unit which receives
light reflected from the facing portion thereof.
15. A semiconductor processing method using semiconductor
processing equipment comprising a transfer chamber having a
plurality of transfer ports disposed at different positions in a
lateral direction, a process chamber connected to the transfer
chamber via one of the plurality transfer ports which performs a
semiconductor processing on a substrate to be processed, a transfer
arm device arranged in the transfer chamber which transfers the
substrate to be processed via the plurality of transfer ports, a
drive mechanism which extends and retracts the transfer arm device
and turns the transfer arm device around a vertical axis direction,
an inclination adjusting mechanism which adjusts an inclination of
the transfer arm device and a rocking table rockable with respect
to the transfer chamber which supports the transfer arm device,
wherein the inclination adjusting mechanism adjusts an inclination
of the transfer arm device by adjusting an inclination of the
rocking table, the method comprising the steps of: detecting data
on an inclination of the transfer arm device by using a detector;
adjusting an inclination of the transfer arm device based on the
data by using the inclination adjusting mechanism; loading the
substrate to be processed into the process chamber by using the
transfer arm device having the adjusted inclination; and performing
a semiconductor processing on the substrate to be processed in the
process chamber.
16. The method of claim 15, wherein the detector has a plurality of
optical sensors spaced from each other in a lateral direction, each
which measures a distance to a facing portion thereof, and wherein
the method further comprises the step of calculating a location of
the substrate to be processed supported by the transfer arm device
with respect to an imaginary reference surface based on the
distance data obtained by the plurality of optical sensors.
17. The method of claim 15, wherein the detector has a plurality of
optical sensors spaced from each other in a lateral direction, each
which measures a distance to a facing portion thereof and the
plurality of optical sensors are arranged on the dummy substrate
serving as a substitute for the substrate to be processed, and
wherein the method further comprises, before the step of detecting
data on the inclination, the step of arranging the dummy substrate
on a specific mounting table and also arranging the transfer arm
device at a position corresponding to the plurality of optical
sensors above the dummy substrate.
18. The method of claim 15, wherein the plurality of transfer ports
are connected with a plurality of process chambers, and wherein the
step of detecting data on the inclination and the step of adjusting
an inclination of the transfer arm device are performed on each of
the plurality of process chambers.
19. The method of claim 17, wherein the specific mounting table is
a mounting table disposed in the process chamber and which mounts
thereon the substrate to be processed in performing the
semiconductor processing.
Description
FIELD OF THE INVENTION
The present invention relates to a semiconductor processing
equipment having a mechanism for adjusting an inclination of a
transfer arm device and a semiconductor processing method using the
same. The term "semiconductor processing" used herein denotes
various processes required to manufacture a semiconductor device or
a structure, which includes wiring, electrode and the like
connected to the semiconductor device, on a substrate to be
processed by forming a semiconductor layer, an insulating layer, a
conductive layer and the like in a predetermined pattern on the
substrate to be processed, e.g., a semiconductor wafer or a glass
substrate for an LCD (Liquid Crystal Display) or an FPD (Flat Panel
Display).
BACKGROUND OF THE INVENTION
In order to manufacture a semiconductor device, various processes
such as a film forming process, an etching process, an oxidation
process, a diffusion process, an annealing process, a quality
modification process and the like are performed on a semiconductor
wafer, which is a substrate to be processed. In these processes, it
is required to improve a throughput and a production yield, along
with microminiaturization and high-integration of a semiconductor
device. In view of the above, there is known a so-called
multi-chamber type (cluster tool type) semiconductor processing
equipment capable of performing various processes successively
without exposing a wafer to the atmosphere by combining a plurality
of process chambers for performing same or different type processes
via a common transfer chamber. Such type of semiconductor
processing equipment is disclosed in, e.g., Japanese Patent
Laid-open Application No. 2000-127069 (see FIG. 1 thereof), and the
like.
FIG. 12 is a schematic plan view of a conventional multi-chamber
type semiconductor processing equipment. As shown in FIG. 12, the
processing equipment has an atmospheric transfer chamber 10
arranged in parallel with a cassette stage 1. Further, a
multi-joint transfer arm device 11 capable of extending, retracting
and turning is provided in the atmospheric transfer chamber 10. A
hexagonal vacuum transfer chamber 14 is connected with the
atmospheric transfer chamber 10 via two load-lock chambers 12. A
multi-joint transfer arm device 13 capable of extending, retracting
and turning is disposed in the transfer chamber 14. Four vacuum
process chambers 15 (for performing a film forming process or an
etching process, for example) are connected with the transfer
chamber 14. Furthermore, the process chambers 15 are connected with
each other via gate valves 16.
In order to perform the processing, a rack-type cassette container
20 accommodating therein, e.g., 25 sheets of wafers W, is mounted
on the cassette stage 1. Next, one of the wafers W is transferred
from the cassette container 20 to one of the load-lock chambers 12
by the transfer arm device 11. Then, the wafer W is transferred
from the load-lock chamber 12 to the transfer chamber 14 by the
transfer arm device 13. Thereafter, the wafer W is loaded into an
empty process chamber 15 and then subjected to, e.g., an etching
process. In case the wafer W is loaded into the process chamber 15,
first of all, the wafer W is delivered from the transfer arm device
13 onto three lifter pins (not shown) which will be lowered so that
the wafer will be mounted on a mounting table 15a.
After setting an imaginary reference surface in the entire
apparatus, it is checked whether or not a transfer surface of the
wafer W supported by the transfer arm device 13, i.e., a backside
of the wafer W, is aligned with respect to the imaginary reference
surface. In order to accurately exchange the wafer W, the transfer
surface needs to be within .+-.0.3 mm from the imaginary reference
surface throughout the entire access area. Such accuracy is needed
because, in recent times, each of the transfer ports of the gate
valves 16 is formed to have a narrow width, for improving plasma
uniformity by improving symmetry in the process chambers and also
for scaling down opening/closing units of the gate valves 16.
Further, if the backside of the wafer W is tilted with respect to
the imaginary reference surface, when the wafer W is delivered onto
the lifter pins, the three lifter pins are not simultaneously
contacted with the backside of the wafer W, thereby resulting in an
unstable exchange of the wafer W.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a
semiconductor processing equipment capable of transferring a
substrate to be processed with high horizontal stability and a
semiconductor processing method using the same.
In accordance with one aspect of the invention, there is provided a
semiconductor processing equipment including:
a transfer chamber having a plurality of transfer ports disposed at
different positions in a lateral direction;
a process chamber connected to the transfer chamber via one of the
plurality transfer ports, for performing a semiconductor processing
on a substrate to be processed;
a transfer arm device arranged in the transfer chamber, for
transferring the substrate to be processed via the plurality of
transfer ports;
a drive mechanism for extending and retracting the transfer arm
device and turning the transfer arm device around a vertical axis
direction; and
an inclination adjusting mechanism for adjusting an inclination of
the transfer arm device.
In accordance with another aspect of the invention, there is
provided a semiconductor processing method using the semiconductor
processing equipment disclosed in claim 1, the method including the
steps of:
detecting data on an inclination of the transfer arm device by
using a detector;
adjusting an inclination of the transfer arm device based on the
data by using the inclination adjusting mechanism;
loading the substrate to be processed into the process chamber by
using the transfer arm device having the adjusted inclination;
and
performing a semiconductor processing on the substrate to be
processed in the process chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic top view of a semiconductor processing
equipment in accordance with a preferred embodiment of the present
invention.
FIG. 2 shows a vertical sectional view of a vacuum transfer chamber
and a vacuum process chamber of the equipment of FIG. 1.
FIG. 3 describes a perspective view of a transfer port of the
equipment of FIG. 1.
FIG. 4A depicts a sectional view of a rocking table for supporting
a transfer arm device provided in the vacuum transfer chamber of
the equipment of FIG. 1.
FIG. 4B presents a top view of the rocking table of FIG. 4A.
FIG. 5A represents a perspective view for illustrating how to
detect an inclination of the transfer arm device of the equipment
of FIG. 1.
FIG. 5B provides a perspective view of a detector (dummy substrate)
for detecting an inclination of the transfer arm device of FIG.
5A.
FIG. 6 offers an explanatory diagram depicting a control unit for
adjusting an inclination of the transfer arm device in the
equipment of FIG. 1.
FIG. 7 is a flowchart of a process for adjusting an inclination of
the transfer arm device in a mode of using sensor outputs in the
equipment of FIG. 1.
FIG. 8 shows a bottom view of a modified example of the transfer
arm device of the equipment of FIG. 1.
FIG. 9 describes a perspective view of a modified example of the
transfer port of the equipment of FIG. 1.
FIG. 10 provides a schematic top view of a semiconductor processing
equipment in accordance with another preferred embodiment of the
present invention.
FIG. 11 presents a sectional view of a rocking table for supporting
a transfer arm device disposed in a vacuum transfer chamber of the
equipment of FIG. 10.
FIG. 12 offers a schematic top view of a conventional multi-chamber
type semiconductor processing equipment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present inventor has studied a transfer misalignment of
conventional semiconductor processing equipments while developing
the present invention and reached to a conclusion to be described
hereinafter.
Recently, along with a trend for a scaling up of a wafer W, the
transfer arm device 13 is extended, accordingly, so that an access
area thereof becomes enlarged. As a result, it becomes difficult to
ensure transfer accuracy with respect to an imaginary reference
surface throughout the entire access area. Especially, in case the
transfer arm device 13 for supporting the wafer W is extended, it
is difficult to ensure the transfer accuracy.
In order to align the backside of the wafer W with the imaginary
reference surface, there can be provided a mechanism for adjusting
a height of the transfer arm device 13 (Z-axis adjusting
mechanism). However, if the Z-axis is tilted by any reason
whatsoever, the wafer W is tilted with respect to the imaginary
reference surface, which hinders the height adjustment. Such
phenomenon occurs because a bottom portion of the transfer chamber
14, where the transfer arm device 13 is disposed, becomes uneven
due to a deformation caused by a stress generated by a vacuum
exhaust, a limitation of manufacturing precision or the like, for
example.
Besides, there is considered a configuration, wherein the number of
process chambers 15 connected with the transfer chamber 14
increases and the transfer arm device 13 accesses each of a
plurality of process chambers 15 in a lateral sliding motion. In
accordance with such configuration, it is possible to improve a
processing efficiency or carry out a batch production, for example.
In this case, however, the access area of the transfer arm device
13 becomes enlarged further more, so that the effect of the
unevenness of the bottom portion of the transfer chamber 14
increases. Moreover, if an area of the bottom portion of the
transfer chamber 14 is enlarged, the force applied thereto during
the vacuum exhaust increases and, thus, the unevenness of the
bottom portion cannot be suppressed. Hence, it is more difficult to
ensure the transfer accuracy.
Hereinafter, preferred embodiments of the present invention will be
described with reference to the accompanying drawings. Further,
like reference numerals will be given to like parts having
substantially same functions, and a redundant description thereof
will be omitted unless it is necessary.
FIG. 1 is a schematic top view of a semiconductor processing
equipment in accordance with a preferred embodiment of the present
invention. FIG. 2 shows a vertical sectional view of a vacuum
transfer chamber and a vacuum process chamber of the equipment of
FIG. 1. As shown in FIG. 1, the processing equipment has a cassette
stage 2 capable of mounting thereon a plurality of rack-type
cassette containers 20, each accommodating therein, e.g., 25 sheets
of semiconductor wafers W as substrates to be processed. Further, a
transfer stage 21 is adjacently arranged on one side surface of the
cassette stage 2 along a longitudinal direction thereof. Moreover,
a multi-joint transfer arm device 22 capable of extending,
retracting and turning is provided on the transfer stage 21 to
exchange the wafers W. Since the transfer arm device 22 is arranged
such that it can slide along a guide rail 23, it can access the
wafers W in any of the cassette containers 20.
Load-lock chambers 24A and 24B serving as preliminary vacuum
chambers, each having a mounting portion for mounting thereon the
wafers W, are connected to a rear portion of the transfer stage 21
via gate valves 25A and 25B, respectively. Further, a vacuum
transfer chamber 3 capable of exhausting an inner space thereof to
vacuum is connected to rear portions of the load-lock chambers 24A
and 24B via gate valves 26A and 26B, respectively. The transfer
chamber 3 is formed in a polygonal shape, e.g., a hexagonal shape,
seen from above. Moreover, a plurality of transfer ports 33 is
arranged on six side surfaces of the transfer chamber 3. In other
words, the transfer chamber 3 has the plurality of transfer ports
33 arranged at different positions in a lateral direction.
The transfer ports 33 provided on two side surfaces of the transfer
chamber 3 are connected with the load-lock chambers 24A and 24B via
the gate valves 26A and 26B, respectively. Further, the transfer
ports 33 disposed on the other four side surfaces of the transfer
chamber 3 are airtightly connected with, e.g., four vacuum process
chambers 4A, 4B, 4C and 4D, via gate valves 31A, 31B, 31C and 31D,
respectively. The transfer chamber 3 can be formed in a circular
shape or an elliptic shape, for example, as long as it can be
radially connected with the process chambers 4A.about.4D. An
orienter 27 serving as a device for positioning the wafer W is
connected to one end of the transfer stage 21. The orienter 27
optically monitors a peripheral portion of the wafer W where
notches or the like are formed while rotating the wafer W, thereby
detecting an eccentric amount, an eccentric direction and an
orientation of the wafer W.
The process chambers 4A.about.4D are set to perform same or
different type processes among various processes such as a film
forming process, a diffusion process, an etching process and the
like. For example, in a process chamber for performing the etching
process, a silicon oxide film or a silicon nitride film can be
etched by using a CF-based processing gas. Or, a tungsten silicide
film or a polycrystalline silicon film can be etched by using a
single gas such as Cl-based gas, HBr-based gas, SF-based gas,
O.sub.2 gas, He gas and the like or by using a mixture of these
gases.
For instance, in case the same type processes are performed on the
plurality of wafers W in parallel, same type process chambers are
selected. On the other hand, in case a series of different type
processes are performed on the single wafer W, for example, in case
the silicon oxide film is etched and, then, the tungsten silicide
film is etched, different type process chambers are selected. FIG.
2 illustrates an example of the process chambers 4A.about.4D, i.e.,
an etching process chamber for etching the wafer W under a vacuum
atmosphere by using plasma.
The etching process chamber 4A (4B.about.4D) has an airtight vessel
41 for forming a vacuum state. Further, a gas shower head 42
serving as an upper electrode is disposed on a ceiling portion of
the airtight vessel 41. Accordingly, a processing gas containing,
e.g., halocarbon gas, O.sub.2 gas, Ar gas and the like, is supplied
through the gas shower head 42 to the airtight vessel 41. Moreover,
a gas exhaust port 45 for exhausting the processing gas is formed
on a bottom portion of the airtight vessel 41.
A mounting table 43 for mounting thereon the wafer W and also
serving as a lower electrode is installed in the airtight vessel 41
such that it faces the gas shower head 42. Further, a focus ring 44
is provided on the mounting table 43 to surround an outer periphery
of the wafer W with a gap therebetween. Moreover, an RF power
supply (not shown) for applying a high frequency electric field for
generating plasma is connected with the upper electrode (the gas
shower head 42). Furthermore, an RF power supply (not shown) for
applying a bias voltage is connected with the lower electrode (the
mounting table 43).
Vertically extending through holes 43a are formed through a surface
of the mounting table 43. Further, three lifter pins 46 for
supporting the backside of the wafer W are disposed such that they
can be protruded and depressed through the through holes 43a. Each
of the lifter pins 46 is connected with a common supporting plate
47 and can move vertically by a driver 48 connected to the
supporting plate 47. Moreover, bellows 49 for maintaining an
airtight state are provided at portions where the lifter pins 46
penetrate the airtight vessel 41.
FIG. 3 describes a perspective view of a transfer port 33 of the
equipment of FIG. 1. The transfer port 33 is formed on a partition
wall 32 (wall surface of the airtight vessel 41) for partitioning
the transfer chamber 3 and the process chambers 4A to 4D. The
transfer port 33 has a horizontally extending strip shape and is
surrounded by a frame protruded toward the transfer chamber 3. A
gate valve 31A (31B.about.31D) is positioned such that it blocks
the transfer port 33 (not shown in FIG. 3). When the gate valve 31A
(31B.about.31D) is opened by an opening/closing mechanism (not
shown), the wafer W can be exchanged between the transfer chamber 3
and the process chambers 4A.about.4D. The transfer port 33 is
formed to have a small length and a narrow width in order to
enhance the uniformity of the semiconductor processing by improving
symmetry in the process chambers 4A.about.4D.
A multi-joint transfer arm device 5 capable of extending,
retracting and turning is disposed on a bottom portion of the
transfer chamber 3. Further, the transfer arm device 5 includes a
hand 51a, e.g., for supporting the backside of the wafer W from
underside, an intermediate arm 51b and a lower arm 51c. The lower
arm 51c is supported at an upper plate 53 of a rocking table 52.
Each of the joint arms 51a.about.51c has therein a transfer unit
(not shown) for transferring a turning operation of a drive
mechanism 55.
FIG. 4A depicts a sectional view of the rocking table 52 for
supporting the transfer arm device 5 provided in the vacuum
transfer chamber 3 of the equipment of FIG. 1. FIG. 4B presents a
top view of the rocking table 52 of FIG. 4A. As shown in FIG. 4A,
the rocking table 52 includes a cylindrical casing 54 having a
bottom surface. In the casing 54, a drive mechanism 55, for
extending and retracting the transfer arm device 5 and turning it
around a vertical axis direction, is provided. To be specific, the
drive mechanism 55 is formed of a motor for extending and
retracting the transfer arm device 5, a motor for turning the
entire transfer arm device 5 and the like. Accordingly, the
transfer arm device 5 is able to extend, retract and turn while
supporting the wafer W, for example.
The rocking table 52 is positioned such that it penetrates an
opening 3a formed on the bottom portion of the transfer chamber 3.
The opening 3a is closed from the underside by a downwardly
protruded cover 57. Further, at a center of an outer bottom portion
of the casing 54 of the rocking table 52, a spherical protrusion
58a protruded downwardly is provided. The spherical protrusion 58a
is movably insertion-fitted to a support portion 58b provided on an
inner surface of the cover 57, thereby forming a universal joint
capable of tilting the rocking table 52 in any direction of
360.degree..
The casing 54 of the rocking table 52 is supported from the
underside by, e.g., three, adjusters 6A, 6B and 6C disposed on the
inner surface of the cover 57, each being separately movable in a
vertical direction. The adjusters 6A, 6B and 6C are provided, e.g.,
on a same circle about the spherical protrusion 58a (see FIG. 4B).
Further, the adjusters 6A.about.6C form an inclination adjusting
mechanism (tilt adjusting mechanism) for adjusting an inclination
of the transfer arm device 5 by adjusting an inclination of the
rocking table 52. By adjusting the respective heights of the
adjusters 6A, 6B and 6C, the inclination of the transfer arm device
5 and that of the rocking table 52 can be adjusted together in any
direction of 360.degree. around a center of the spherical
protrusion 58a. The installation number of the adjusters
6A.about.6C can increase without being limited to three.
A bellows (pliable wall) 59 for maintaining an airtight state of
the transfer chamber 3 is provided between an upper peripheral
portion of the casing 54 of the rocking table 52 and the bottom
portion of the transfer chamber 3. The bellows 59 separates a
space, where the adjusters 6A.about.6C and the universal joints 58a
and 58b are arranged, from an inner space of the transfer chamber
3. Further, the bellows 59 allows the rocking table 52 to move in
any direction of 360 degrees.
As shown in FIG. 4A, each adjuster 6A (6B, 6C) have a guide 61A
(61B, 61C), which is arranged in an inner surface of the cover 57
and extended upwardly. Moreover, a male screw 62A (62B, 62C) is
formed on surfaces of the guide 61A (61B, 61C) and screwed with a
female screw 63A (63B, 63C) formed on shaft holes of a first gear
64A (64B, 64C). In addition, a protrusion 65A (65B, 65C) for
supporting the casing 54 from underside is formed on upper surfaces
of the first gear 64A (64B, 64C).
A second gear 66A (66B, 66C) is provided to be screw-coupled to the
first gear 64A (64B, 64C). Further, the second gear 66A (66B, 66C)
is attached to a driving unit, e.g., a rotational shaft of a motor
67A (67B, 67C). If the second gear 66A (66B, 66C) rotates about a
vertical axis by driving the motor 67A (67B, 67C), the first gear
64A (64B, 64C) also rotates about the vertical axis. If the first
gear 64A (64B, 64C) rotates, the female screw 63A (63B, 63C) is
engaged with the male screw 62A (62B, 62C) of the guide 61A (61B,
61C), thereby moving the first gear 64A (64B, 64C) in an axial
direction (vertical direction). In other words, the protrusion 65A
(65B, 65C) supporting the casing 54 is vertically moved by driving
the motor 67A (67B, 67C).
In the semiconductor processing equipment shown in FIG. 1, in order
to perform the processing, the rack-type cassette container 20
accommodating therein, e.g., 25 sheets of wafers W, is mounted on
the cassette stage 2. Next, one of the wafers W is transferred from
the cassette container 20 to the orienter 27 to be positioned by
the transfer arm device 22. Then, the wafer W is transferred from
the orienter 27 to an empty load-lock chamber 24A (24B) via the
gate valve 25A or 25B by the transfer arm device 22.
After the load-lock chamber 24A (24B) is depressurized, the wafer W
is transferred from the load-lock chamber 24A (24B) to the transfer
chamber 3 by the transfer arm device 5. Next, the wafer W is loaded
into an empty process chamber, e.g., 4A (4B, 4C, 4D) to be
subjected to a specific processing. In case the wafer W is loaded
into the process chamber 4A (4B, 4B, 4D), first of all, the wafer W
is delivered from the transfer arm device 5 onto three lifter pins
46 (see FIG. 2), and then mounted on the mounting table 43 by
lowering the lifter pins 46. After being subjected to the specific
processing in the process chamber 4A (4B, 4C, 4D), the wafer W is
returned to the cassette container 20 by reversely carrying out the
aforementioned loading process.
FIG. 5A represents a perspective view for illustrating how to
detect an inclination of the transfer arm device 5 of the equipment
of FIG. 1. FIG. 5B provides a perspective view of a detector (dummy
substrate) 7 for detecting an inclination of the transfer arm
device 5 of FIG. 5A.
The dummy substrate 7 is set to have the same diameter as that of
the wafer W so that it can replace the wafer W. Three optical
sensors (distance detectors) 71A, 71B and 71C spaced from each
other, for example, are coaxially provided, e.g., on the dummy
substrate 7 about a center of the dummy substrate 7, each having a
light emitting unit and a light receiving unit. The dummy substrate
7 is mounted on the mounting table 43 in the process chamber 4A
(4B, 4C, 4D), for example, and used while the transfer arm device 5
is extended thereabove. At this time, the optical sensors
71A.about.71C are positioned such that they face a fork-shaped
leading end portion and a base portion of the hand 51a. The light
emitting units of the optical sensors 71A.about.71C emit light
toward the hand 51a, whereas the light receiving units thereof
receive light reflected from a facing portion of the hand 51a.
Accordingly, a distance from each optical sensor 71A (71B, 71C) to
the facing portion of the hand 51a is detected based on an
intensity of the light reflected from the hand 51a. To be more
specific, based on the detection result from the three optical
sensors 71A.about.71C, it is possible to detect a tilting direction
of the hand 51a with respect to a vertical axis and a tilting
degree thereof with respect to a horizontal surface. Further, since
a vertical distance from a surface of the mounting table 43 to the
light receiving surfaces of the optical sensors 71A.about.71C can
be obtained, a height difference between the imaginary reference
surface IRF (see FIG. 2) and the backside of the wafer W can be
calculated. Moreover, a communication unit 72 is provided on the
dummy substrate 7 and wirelessly transmits, e.g., via infrared
rays, the distance data (sensor data), i.e., the detection result
from the optical sensors 71A.about.71C, to a control unit 73 to be
described later. The sensor data are sequentially transmitted from
the communication unit 72 to the control unit 73 at specific
intervals.
FIG. 6 offers an explanatory diagram depicting the control unit 73
for adjusting an inclination of the transfer arm device 5 in the
equipment of FIG. 1. The control unit 73 includes a computer system
having a CPU, for example. To be more specific, the control unit 73
includes a communication unit 74 for receiving the detection result
from the optical sensors 71A.about.71C and a storage unit 75 for
storing therein the distance data (from the optical sensors
71A.about.71C to the hand 51a) for each process chamber 4A (4B, 4C,
4D).
The control unit 73 further includes a conversion unit 76 for
obtaining driving instruction values (driving amount) of the three
motors 67A.about.67C based on the three distance data detected by
the optical sensors 71A.about.71C. The three distance data
indicate, in case the height-direction distances between each of
the light receiving surfaces of the optical sensors 71A.about.71C
and the surface of the mounting table 43a are given, relative
position of the hand 51a, i.e., a height difference and an
inclination with respect to the imaginary reference surface IRF.
Moreover, the driving instruction value indicates a driving amount
required to fit the hand 51a to the imaginary reference surface
IRF.
The conversion unit 76 can refer to a preset table in order to
convert the distance data into a driving instruction value. The
table contains a relationship between combinations of the three
distance data and driving amounts (vertical movement amounts) of
the first gears 64A.about.64C with respect to reference positions
by the three motors 67A.about.67C. Further, the conversion process
can be performed on the assumption that the height of the hand 51a
hardly changes. In this case, a combination of differences in the
distance data, e.g., a detection distance difference between the
optical sensors 71A and 71B and that between the optical sensors
71A and 71C, can be converted into driving instruction values.
FIG. 7 is a flowchart of a process for adjusting an inclination of
the transfer arm device 5 in a mode using sensor outputs in the
equipment of FIG. 1.
For example, during a maintenance service of the equipment or at a
randomly selected specific timing, a cover of one of the process
chambers 4A.about.4D is opened and, then, the wafer 7 is mounted on
the mounting table 43, as described in step S1. Next, as shown in
step S2, the transfer arm device 5 is extended until the hand 51a
is positioned where it faces the surface of the dummy substrate 7
(see FIG. 5A). At this time, the wafer W is preferably kept
supported on the hand 51a. Then, as described in step S3, optical
sensors 71A.about.71C acquire distance data to the hand 51a.
Thereafter, the distance data are received by the control unit 73
and then stored in the storage unit 75. The steps S1.about.S3 are
performed on the respective process chambers 4A.about.4D (step S4).
Accordingly, inclinations of the transfer arm device 5 with respect
to each of the process chambers 4A.about.4D are detected.
Next, as shown in step S5, after closing the covers of the process
chambers 4A.about.4D, the operation of the equipment and the
transfer of the wafer are started. To do so, above all, the wafer W
is transferred from the cassette container 20 to the transfer
chamber 3. Thereafter, as shown in step S6, an inclination
adjustment (tilt adjustment) of the transfer arm device 5 is
performed based on the distance data for the process chamber 4A
(4B, 4C, 4D) where the wafer W is transferred. In order to set a
tilt, the distance data stored in the storage unit 75 are converted
into the driving amount of the motors 67A.about.67C by the
conversion unit 76 and then stored in a storage unit 77. The motors
67A.about.67C are controlled by reading out the driving amount.
After the tilt is adjusted, the wafer W held on the hand 51a is
loaded into the corresponding process chamber 4A (4B, 4C, 4D) by
extending the transfer arm device 5. Further, as depicted in step
S7, the wafer W is mounted on the mounting table 43 in the process
chamber 4A (4B, 4C, 4D) by a cooperation of the transfer arm device
5 and the lifter pins 46. Then, as shown in step S8, a specific
semiconductor processing, e.g., an etching process, is
performed.
Meanwhile, in case a different type semiconductor processing is
performed on the wafer W in an additional process chamber 4B (4C,
4D), the aforementioned steps S5.about.S7 are executed on the
corresponding process chamber 4B (4C, 4D) (step S9). The wafer W
that has been subjected to the entire semiconductor processing is
returned to the cassette container 20 via the load-lock chambers
24A or 24B and the transfer stage 21.
In accordance with the aforementioned embodiment, there is provided
a mechanism for adjusting an inclination of the transfer arm device
5 and, specifically, an inclination of the rocking table 52 for
supporting the transfer arm device 5. With such configuration, in
case a scaled-up wafer W is transferred, for example, or even in
case the bottom portion of the transfer chamber 3 is uneven, it is
possible to transfer the wafer W while supporting the backside
thereof with high horizontal stability throughout the entire access
area of the transfer arm device 5. As described above, the transfer
ports 33 are formed to have a narrow width of, e.g., 30 mm.about.50
mm. However, if transferred with such high horizontal stability,
the wafer W can pass through the transfer ports 33 without
collisions. Moreover, since the three lifter pins 46 are
simultaneously contacted with the backside of the wafer W, the
wafer W can be stably exchanged.
The timing of acquiring the distance data with the optical sensors
71A.about.71C is not limited to after the maintenance service of
the equipment is completed. For example, the aforementioned
distance data can also be obtained when the transfer arm device 5
is instructed to perform a transfer operation during an operation
of the equipment or the like. In this case as well, the same
effects of the aforementioned case can be achieved.
The aforementioned tilt adjusting mechanism can perform the
adjustment with respect to the imaginary reference surface IRF,
together with the height adjusting mechanism (Z-axis adjusting
mechanism) for adjusting the height of the transfer arm device 5.
As for the Z-axis adjusting mechanism, there can be employed a
configuration in which the drive mechanism 55 has a function of
vertically moving the transfer arm device 5. In this case as well,
the same effects of the aforementioned case can be achieved.
The optical sensors 71A.about.71C can be provided on the backside
of the dummy substrate instead of the top surface thereof. In this
case, in order to measure the distance, the transfer arm device 5
is extended to a position facing the surface of the mounting table
43 while supporting the dummy substrate. After that, the optical
sensors 71A.about.71C provided on the backside of the dummy
substrate measure the distances to the surface of the mounting
table 43. Accordingly, it is possible to achieve the same effects
of the aforementioned case.
FIG. 8 shows a bottom view of a modified example of the transfer
arm device of the equipment of FIG. 1. In the modified example
shown in FIG. 8, the optical sensors 71A.about.71C are provided on
the backside of the hand 51a of the transfer arm device 5. In this
case, in order to measure the distance, the transfer arm device 5
is extended to a position facing the surface of the mounting table
43. After that, the optical sensors 71A.about.71C provided on the
backside of the hand 51a measure respective distances to the
surface of the mounting table 43. Accordingly, the same effects of
the aforementioned case can be achieved.
FIG. 9 describes a perspective view of a modified example of the
transfer port of the equipment of FIG. 1. In the modified example
shown in FIG. 9, the optical sensors 71A and 71B are provided on
bottom surface of the transfer port 33 of each process chamber 4A
(4B, 4C, 4D). In this case, in order to measure the distance, the
transfer arm device 5, e.g., supporting the wafer W, is extended to
a position facing the optical sensors 71A and 71B. After that, the
optical sensors 71A and 71B, which are provided on the bottom
surface of the transfer port 33, measure respective distances to
the backside of the wafer W. Hence, the same effects of the
aforementioned case can be achieved. Moreover, if the distance data
from the corresponding port 33 as well as those from the
aforementioned mounting table 43 are allowed to be acquired, a more
accurate control can be realized.
In case an optical sensor is provided at the transfer port 33 or
the hand 51a, the optical sensor is exposed to a processing gas.
Therefore, in this case, it is preferable to install a device,
e.g., a heater, for heating a light receiving unit of the
corresponding optical sensor. Consequently, it is possible to
prevent a byproduct film generated by the processing gas from being
deposited to the light receiving unit, thereby enabling to obtain
stable distance data.
The distance can be measured not only by using the optical sensors
71A.about.71C but also by using a CCD camera, for example. In this
case, the distance is detected based on image data captured by the
CCD camera. Accordingly, the same effects of the aforementioned
case can be achieved.
FIG. 10 provides a schematic top view of a semiconductor processing
equipment in accordance with another preferred embodiment of the
present invention. FIG. 11 presents a sectional view of a rocking
table for supporting a transfer arm device disposed in a vacuum
transfer chamber of the equipment of FIG. 10. The equipment shown
in FIG. 10 has the same configuration as that of the equipment of
FIG. 1 except that the transfer arm device 5 accesses six process
chambers 4A.about.4F connected with the transfer chamber 3 in a
sliding movement.
In order to allow the transfer arm device 5 to move in a sliding
motion, as shown in FIG. 11, a box-shaped moving body 8
corresponding to the cover 57 shown in FIG. 4 is disposed on the
bottom portion of the transfer chamber 3 with a gap therebetween.
The moving body 8 supports the rocking table 52 from underside and
has therein the adjusters 6A.about.6C. Further, the moving body 8
is supported such that it can travel along a guide rail 81 formed
on the bottom portion of the transfer chamber 3. Moreover, the
moving body 8 moves along the guide rail 81 as a unit with the
transfer arm device 5 by a driving unit (not shown) for a sliding
movement.
For instance, in case the wafer W is loaded into the process
chambers 4B.about.4E provided at the rear portion, first of all,
the wafer W is unloaded from the load-lock chamber 24A or 24B.
Next, the moving body 8 moves in a sliding motion toward the rear
portion until it reaches a specific position. Thereafter, the wafer
W is loaded into one of the process chambers 4B.about.4E by
extending the transfer arm device 5. With such configuration, the
same effects of the aforementioned case can be achieved.
Especially, in this case, the transfer arm device 5 can be easily
deformed because a load caused by the vacuum state becomes heavy
due to a scaling up of the transfer chamber 3. Therefore, the tilt
adjustment of the transfer arm device 5 will be effective.
The adjuster 6A (6B, 6C) is not limited to the aforementioned
configuration in which they are raised and lowered by using the
guide 61A (61B, 61C) and the first gear 64A (64B, 64C) together. As
for the adjuster 6A (6B, 6C), there can be used other devices such
as a linear actuator, a parallel link or the like. With such
configuration, the same effects of the aforementioned case can be
achieved.
The tilt adjustment is performed not only before the transfer arm
device 5 supporting the wafer W is loaded into the process chamber
4A (4B, 4C, 4D). For example, the tilt adjustment can be carried
out twice, i.e., before the transfer arm device 5 is loaded into
the process chamber 4A (4B, 4C, 4D) and after the transfer arm
device 5 is loaded into the process chamber 4A (4B, 4C, 4D) but
before the wafer W is delivered onto the lifter pins 46. In this
case, as described above, it is possible to use the distance data
from the transfer port 33 as well as those from the mounting table
43. Further, the tilt adjustment can be performed only after the
transfer arm device 5 is loaded into the process chamber 4A (4B,
4C, 4D), which is effective in case of using the transfer port 33
having a scaled-up size depending on types of processes assigned to
the process chamber 4A (4B, 4C, 4D).
The transfer arm device 5 can be supported on a ceiling portion or
a sidewall of the transfer chamber 3 instead of the bottom portion
thereof. In this case as well, the same effect of the
aforementioned case can be obtained.
The tilt can be adjusted to reduce an acceleration generated by
starting or stopping operations of extending, turning or sliding
the transfer arm device 5. Accordingly, when the operations are
started or stopped, the wafer W can be prevented from sliding on
the hand 51a, thereby enabling to suppress a misalignment of the
wafer W. As a result, the wafer W can be more stably exchanged and,
also, the throughput can be improved by increasing a transfer
speed.
While the invention has been shown and described with respect to
the preferred embodiments, it will be understood by those skilled
in the art that various changes and modification may be made
without departing from the scope of the invention as defined in the
following claims.
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